In 3GPP (3rd Generation Partnership Project) which is a standardization project, standardization of Evolved Universal Terrestrial Radio Access (hereafter referred to as “EUTRA”) is performed in which high speed communication is realized by adopting an OFDM (Orthogonal Frequency-Division Multiplexing) communication scheme and flexible scheduling with a predetermined frequency and time unit called a resource block.
Moreover, in the 3GPP, a discussion on Advanced EUTRA that realizes higher-speed data transmission and has an upward compatibility with the EUTRA has been carried out. In the EUTRA, a communication system is premised to have a network in which base station apparatuses are composed of substantially the same cell configurations (cell sizes), but in the Advanced EUTRA, a discussion has been carried out on a communication system that is premised to have a network (Heterogeneous Network) in which base station apparatuses (cells) having different configurations are mixed in a same area.
In a communication system in which cells (small cells) having a smaller cell radius than a conventional one are deployed like the heterogeneous network, a function of connecting to a base station of a conventional cell having a large radius (macro cell) and a base station of a small cell at the same time (dual connectivity) is being discussed (NPL 1).
For example, when a terminal apparatus tries to realize dual connectivity between a cell (macro cell) having a large cell radius (cell size) and a cell (small cell (or picocell)) having a small cell radius, because of low speed of a backbone line (Backhaul) between the macro cell and the small cell, when the terminal apparatus provides feedback information of the small cell via the macro cell, efficiency of scheduling in the small cell is likely to be reduced due to delay.
Moreover, proposed in NPL 2 is that when a terminal apparatus connects with base station apparatuses of a plurality of cells, plural pieces of uplink control information are exchanged between the terminal apparatus and a base station apparatus by allocating a physical uplink control channel to a plurality of uplinks.